//定义数组
var arr = [1, 2, 3, 4];
var arr1 = [1, 3, 4, 5];
var arr2 = ['hello', 'javascript', 'html'];
//元组类型
var foo = ['hello', 100];
var obj = { name: 'jack', age: 18 };
console.log(obj.name);
// let userName:string = 'jack'
var userName = 'jack';
var obj1 = { name: 'rose', age: 18 };
var a = 'hello';
a = 100;
a = true;
